just to clarify my position: I don't pretend to substitute the currently used gettext .po files that are used for the GUI, but only the Wiki pages (also, I agree with your comment about Launchpad, etc.). I strongly believe in "using the right tool for the task". In the same way that I don't agree with the decision that was taken to convert the tutorials to .po files for translation, and then converting them back again to svg format, I would not find it "logical" to convert the wiki texts to .po and then back again. I think that that would be a waste of effort if there already is an easier way to automate the task.
I don't have any experience using translatewiki (yet), so I don't know if it really would be an easier way to keep inkscape's wiki translations up to date. Could you shed some light here?
I personally prefer .po files because I'm most efficient with them as
opposed to different web interfaces like Launchpad, Pootle,
Translatewiki etc. But I understand other, especially novice
translators might be more comfortable with those. I have no problem
with adopting and supporting a website as an alternative translation
platform but I expect the good old way to remain available.
I've been using Translatewiki to translate MediaWiki for a few years
now and I've seen its development. Are there any specific question you
would like to ask?